XMPP Server contains a vulnerability that could allow an unauthenticated, remote attacker to conduct spoofing attacks against a targeted server.

The vulnerability exists because the affected server process fails to validate identification information from arbitrary domain servers. An unauthenticated, remote attacker could exploit the vulnerability by transmitting spoofed authentication information through a verify response request to the affected server process, which could bypass security restrictions imposed by the server. This could allow the attacker to validate a malicious domain and initiate malicious communication to the targeted system.

XMPP.org has confirmed the vulnerability and released software updates.

Warning Indicators

XMPP Server jabberd daemon versions 2.2.16 and prior are vulnerable.

IntelliShield Analysis

To exploit the vulnerability the attacker must transmit spoofed verify response requests to the targeted system. To transmit the requests, the attacker must have access to the trusted network. This access requirement could limit likelihood of a successful exploit.

The Extensible Messaging and Presence Protocol (XMPP) protocol supported by the affected server provides signaling for VoIP, video, file transfer, and messaging services that are used by various instant messaging and chat programs on social networking sites. Those services could also be vulnerable to an exploit.

Vendor Announcements

XMPP.org has released a security advisory at the following link: server-dialback

Apple has released security advisories at the following links: HT5533 and HT5672

An unauthenticated, remote attacker could exploit the vulnerability to transmit spoofed validation requests to the targeted server. This could allow the attacker to validate a malicious domain that may initiate communication with the targeted server.

Technical Information

The vulnerability exists in the Server Dialback Protocol implementation in XMPP Server. The servers use the protocol dialback key to verify the identity of peer domains based on DNS. Due to this vulnerability, the server fails to verify the key with an authoritative DNS entry for the server, and it could validate authorization requests from invalid domain servers.

An unauthenticated, remote attacker could exploit the vulnerability by transmitting spoofed dialback responses to the targeted system. A successful attack could allow the attacker to bypass security restrictions imposed by the protocol and gain unauthorized access to the targeted system by spoofing authentication to the targeted system.

Safeguards

Administrators are advised to apply the appropriate updates.

Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.

Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.

Patches/Software

XMPP Server users are advised to upgrade the server code as determined by the security advisory at the following link: server-dialback

Version 1, August 27, 2012, 2:23 PM: XMPP Server contains a vulnerability that could allow an unauthenticated, remote attacker to conduct spoofing attacks against a targeted server. Updates are available.

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